U.S. patent number 6,056,752 [Application Number 09/177,855] was granted by the patent office on 2000-05-02 for fixation of cruciate ligament grafts.
This patent grant is currently assigned to Smith & Nephew, Inc.. Invention is credited to Gregory J. Roger.
United States Patent |
6,056,752 |
Roger |
May 2, 2000 |
Fixation of cruciate ligament grafts
Abstract
The present invention comprises a method for the reconstruction
of a cruciate ligament of a patient. A connection device for
connecting a cruciate ligament replacement graft to the femur of a
patient is also described. The arrangement can result preferably in
the femoral end of the graft being held in the femoral hole without
any spring or elasticity in the connection between the graft and
the femoral bone. At this end of the graft, at least, the practical
and theoretical problems of screw fixation are avoided.
Inventors: |
Roger; Gregory J. (Crows Nest,
AU) |
Assignee: |
Smith & Nephew, Inc.
(Memphis, TN)
|
Family
ID: |
3804283 |
Appl.
No.: |
09/177,855 |
Filed: |
October 23, 1998 |
Foreign Application Priority Data
Current U.S.
Class: |
623/13.12;
606/232; 623/13.17; 606/330; 606/151 |
Current CPC
Class: |
A61F
2/0811 (20130101); A61B 17/1714 (20130101); A61F
2/0805 (20130101); A61B 17/1764 (20130101); A61B
2017/0403 (20130101); A61F 2002/0858 (20130101); A61B
2017/0404 (20130101); A61B 2017/0414 (20130101); A61F
2002/0852 (20130101); A61F 2002/087 (20130101); A61F
2002/0882 (20130101) |
Current International
Class: |
A61B
17/16 (20060101); A61B 17/17 (20060101); A61F
2/08 (20060101); A61B 017/56 () |
Field of
Search: |
;606/72,88,151,232
;623/13 |
References Cited
[Referenced By]
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Other References
European Patent Abstracts, Week 9240, p. 235, EP 506420-A1. .
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Kurosaka M. et al., Am. Journal of Sports Med., vol. 15, No. 3, pp.
225-229, "a Biochemical Comparison of Different Surgical Techniques
of Graft Fixation in Anterior Cruciate Ligament Reconstruction".
.
Lambert K.L., Clinical Orthopedics and Related Research, No. 72,
Jan./Feb. 1983, pp. 85-89, "Vascularized Patella Tendon Graft with
Rigid internal Fixation for Anterior Cruciate Ligament
Insufficiency". .
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American Journal of Sports Medicine, (22) 2:240-247, Mar./Apr.
1994..
|
Primary Examiner: Buiz; Michael
Assistant Examiner: Woo; Julian W.
Attorney, Agent or Firm: Fish & Richardson P.C.
Claims
What is claimed is:
1. A connection device for connecting a cruciate ligament
replacement graft to a femur of a patient, the connection device
including an elongate member that is pivotally connected at one end
to a cross member intermediate its ends, the elongate member being
provided, at or adjacent its other end, with means to enable it to
be connected to a suitable graft.
2. The connection device of claim 1 wherein the elongate member of
the connection device has a hook at the one end so that it may be
conveniently pivotally connected to the cross member.
3. The connection device of claim 1 wherein the elongate member has
at an end distal the one end means to enable the graft to be
connected to the elongate member.
4. The connection device of claim 3 wherein a suture is connected
to each end of the cross member to assist in passing the connection
device into, and partially through, a hole in the femur.
5. The connection device of claim 4 wherein the means to enable the
graft to be connected to the elongate member comprise an eye
through which the graft may be threaded.
6. The connection device of clam 5 wherein the eye is formed by an
annular extension of the elongate member.
7. The connection device of claim 6 wherein the annular extension
has a cross-sectional dimension such that when a graft is draped
through the eye and the elongate member positioned in the hole the
graft will be firmly engaged on both sides of the eye with the bone
surrounding the hole.
8. The connection device of claim 6 wherein the elongate member is
of such a length that the eye will be only just completely inside
the hole in the femur at its condylar notch end.
9. The connection device of claim 1 wherein in the event that the
graft comprises a number of graft strands that are connected to the
connection means by draping the graft strands through an eye at the
other end of the elongate member, the connection between the graft
and the eye approximates the natural connections of cruciate
ligament to the femur.
10. The connection device of claim 9 wherein the inside surface of
the eye is arcuate with a portion of that surface diametrically
opposite the elongate member closer to the elongate member than
portions on either side of that portion.
11. A connection means for connecting a cruciate ligament graft to
a patient's femur, the connection means having a body that has at
one end an eye or like formation through which the graft may be
threaded, the eye or like formation having a bearing surface
against which the graft will, in use, bear, the bearing surface
being arcuate along its length and having a portion intermediate
its ends that is closer to the body of the connection means than
portions on either side of that portion.
12. The connection device of claim 11 wherein the end of the body
distal the one end is provided with a hook that can be positioned
to extend through a transverse hole through a bone block at an end
of the graft.
13. The connection device of claim 11 wherein the graft includes a
bone block at one or both ends of the graft.
14. The connection device of claim 13 wherein the bone block is so
sized that it is a tight fit in at least one dimension in a hole in
the femur or a hole in a tibia so as to assist integration of the
bone block with the bone surrounding the hole.
15. The connection device of claim 11 wherein the tendon graft
comprises tendon or tendons derived from the hamstring tendons of
the patient or from the Achilles tendons of cadavers.
16. The connection device of claim 15 wherein the tendons are the
semitendonosus and gracilis tendons of the patient harvested from
the same leg as the deficient cruciate ligament.
17. A method for the reconstruction of a cruciate ligament of a
patient comprising the steps of:
a) forming a graft from tendon, other soft tissue or artificial
tendon;
b) forming a hole through the patient's femur opening at one end at
a suitable point in the intercondylar notch in the femur;
c) forming a suitably positioned hole through the patient's tibia
opening at one end adjacent the cross-sectional medial tibial spine
of the tibia;
d) connecting one end of the graft to an elongate shaft of a
connection device, which device comprises the elongate shaft and a
cross member pivotally connected intermediate its ends to one end
of the elongate shaft;
e) passing the connection device into the hole in the femur from
the intercondylar notch end thereof with the cross member lying
alongside the elongate member until the cross member extends
completely through the hole in the femur;
f) rotating the cross member so that it lies transversely to the
elongate member and pulling the connection device back so that the
cross member lies against the surface of the femur;
g) simultaneously or sequentially drawing the other end of the
graft at least into the hole in the tibia; and
h) after tensioning the graft appropriately, securing the other end
of the tendon graft to the tibia.
18. The method of claim 17 wherein the tendon or tendons forming
the tendon graft are doubled over about their mid-point and trimmed
to a desired length.
19. The method of claim 18 wherein the resulting free ends are then
bound together, over a length approximately equal to the length of
the tendons that extend through the hole in the tibia, after being
threaded through the eye in the connection device.
20. The method of claim 19 wherein the ends of the tendon or
tendons are bound together using a Krakow suture, a roman sandal
suture or a modified baseball stitch.
21. The method of claim 20 wherein a suture is connected to the
graft at the tibial end, the suture being used to draw the tendon
graft through the tibial hole and to tension the graft prior to
insertion of the fixation device in the tibia.
22. The method of claim 21 wherein the suture is also used to
connect the graft to fixation means on the surface of the
tibia.
23. The method of claim 17 wherein the tibial hole is formed by
drilling a hole having a cross-sectional area just sufficient to
receive the other end portion of the tendon graft.
24. The method of claim 17 wherein in the case of an anterior
cruciate ligament replacement, a guide hole is drilled from the
outside and is guided so that at its exit from the tibia it will be
at the coronal level of the median tibial eminence 2/3 of the way
across the notch, lateral to medial, so as to remove the anterior
cruciate ligament stump.
25. The method of claim 17 wherein the free end of the graft is
drawn right through the tibial hole and secured, directly or by
sutures, to a lateral surface of the tibia by suitable fastening
means such as staples, staple plates, or screws.
26. The method of claim 25 wherein the graft is brought firmly into
contact with the tibial bone surrounding this hole in a manner that
substantially prevents movement of the graft within that hole.
27. A method for connecting a multi-strand graft to a bone
comprising the steps of extending the graft through a hole in the
bone, positioning an abutment means between the strands of the
graft and drawing the abutment means against the strands of the
graft to urge them into contact with the bone surrounding the
hole.
28. The connection device of claim 1, wherein the elongate member
is inelastically connected to the cross member.
29. The connection device of claim 9, wherein the eye is crescent
shaped.
Description
TECHNICAL FIELD
The present invention relates to a method for the reconstruction of
a cruciate ligament of a patient. More particularly it relates to
such a method in which a graft is used to replace a ruptured
anterior or posterior cruciate ligament The present invention also
relates to a device for use in such cruciate ligament
reconstruction operations.
BACKGROUND ART
As is well known the human knee comprises an articulation of the
femur, the tibia and the patella. The femur and the tibia are
maintained in a condition of stable articulation by a number of
ligaments of which the principal ones are the anterior and
posterior cruciate ligaments and the collateral ligaments. The
rupture of the anterior cruciate ligament is relatively commonly
encountered as a result of sporting injury or the like. This
rupture leads to knee instability and can be a debilitating injury.
Though less common the rupture of the posterior cruciate ligament
can be equally disabling.
There have been a number of procedures designed to reconstruct the
anterior cruciate ligament. Initially, attempts were made to
replace the anterior cruciate ligament with tendons harvested from
elsewhere in the body. These tendons were connected respectively to
the femur and the tibia by staples, screws or the like inserted
exteriorly into the bone and forming an external attachment to
which the tendon could be connected externally of the bone. In some
cases, the tendon passed over the top of one of the femoral
condyles before attachment to the femur and in other cases a hole
was drilled through the femur from outside the bone into the
intercondylar notch. These attempts at cruciate ligament
reconstruction had mixed success. The tendon tended to break at its
point of connection to the bone, or become loose over time,
indicating that the tendon bone interface was crucial for effective
cruciate ligament reconstruction.
These problems led to the use of bone-tendon-bone grafts generally
harvested from mid-third patella tendon with a bone block at each
end. Each bone block is inserted into an appropriate hole drilled
in the femur or the tibia and secured in place by a screw driven
between the wall of the hole and the bone block. While this system
has been very successful in many respects a significant number of
patients continue to have
patella-femoral problems, especially over the mid-third patella
tendon donor site.
In an effort to overcome these problems it has been proposed to
suture hamstring tendon to a bone block derived from coring the
tibial tunnel and to thereby manufacture a bone/tendon/bone graft
similar to a mid-third patella tendon graft. The present inventors
have found that the bone quality is extremely variable. This
results in poor fixation and poor intra-operative pull-out strength
in some cases. This procedure was also found to be a very demanding
surgical procedure, and therefore difficult to reproduce.
It is also known to provide a method for the reconstruction of the
anterior cruciate ligament of a patient which comprises the steps
of:
a) forming a tendon graft from tendon, other soft tissue or
artificial tendon;
b) forming a hole through the patient's femur from a suitable point
in the intercondylar notch therein anteriorly and laterally, the
cross-sectional area of at least an end portion of the hole through
the femur adjacent the intercondylar notch being sufficient to
receive an end of the tendon graft and a suitable screw, peg or
other fixation device having a leading end and a trailing end;
c) forming a suitably positioned hole through the patient's tibia
opening at one end adjacent the cross-sectional medial tibial spine
of the tibia of an area sufficient to receive the other end of the
tendon graft;
d) drawing one end of the tendon graft into the enlarged end
portion of the hole in the femur and simultaneously or sequentially
drawing the other end of the tendon graft into the hole in the
tibia;
e) inserting the leading end of a fixation device into the hole in
the femur from the intercondylar notch end thereof until the
trailing end of the fixation device is at least adjacent that end
of the hole, and the tendon graft is pressed directly and firmly
against a sidewall of the hole in the femur by the fixation device;
and
f) after tensioning the tendon graft appropriately, securing the
other end of the tendon graft to the tibia.
The foregoing method is a significant improvement over the
preceding methods however it still suffers from the theoretical and
practical problems of placing a screw or like fastener into a blind
hole between the graft and the bone surrounding the hole. The
present invention provides the public with an alternative that does
not necessarily require the placement of a screw into the hole
carrying the graft through either the tibia or the femur.
DISCLOSURE OF INVENTION
In a first aspect the present invention consists in a method for
the reconstruction of a cruciate ligament of a patient comprising
the steps of:
a) forming a graft from tendon, other soft tissue or artificial
tendon;
b) forming a hole through the patient's femur opening at one end at
a suitable point in the intercondylar notch in the femur;
c) forming a suitably positioned hole through the patient's tibia
opening at one end adjacent the cross-sectional medial tibial spine
of the tibia;
d) connecting one end of the graft to the elongate shaft of a
connection device, which device comprises an elongate shaft and a
cross member pivotally connected intermediate its ends to one end
of the elongate shaft;
e) passing the connection device into the hole in the femur from
the intercondylar notch end thereof with the cross member lying
alongside the elongate member until the cross member extends
completely from the other end of the hole in the femur;
f) rotating the cross member so that it lies transversely to the
elongate member and pulling the connection device back so that the
cross member lies against the surface of the femur;
g) simultaneously or sequentially drawing the other end of the
graft at least into the hole in the tibia; and
h) after tensioning the graft appropriately, securing the other end
of the tendon graft to the tibia.
In a second aspect the present invention relates to a connection
device for connecting a cruciate ligament replacement graft to the
femur of a patient, the connection device including an elongate
member that is pivotally connected at one end to a cross member
intermediate its ends, the elongate member being provided,
preferably at or adjacent its other end, with means to enable it to
be connected to a suitable graft.
The arrangement according to the present invention, at least in
preferred embodiments, is that the femoral end of the graft is held
in the femoral hole without any spring or elasticity in the
connection between the graft and the femoral bone. At this end of
the graft, at least, the practical and theoretical problems of
screw fixation are avoided.
In preferred embodiments of the invention the elongate member of
the connection device has a hook at the one end so that it may be
conveniently pivotally connected to the cross member. It preferably
has at its other end means to enable the graft to be connected to
the elongate member. A suture is preferably connected to each end
of the cross member to assist in passing the connection device
into, and partially through, the hole in the femur. Tension on one
of these sutures and on the graft, in opposite directions, will
hold the cross member in its orientation alongside the elongate
member. When the cross member projects from the hole this tension
is released and the cross member is pivoted into a position in
which it lies transversely to the elongate member by pulling on the
other of the sutures connected to the cross member. In this
position any tension on the graft is resisted by the cross member
bearing against the surface of the femur adjacent to the outside
end of the hole.
The means to enable the graft to be connected to the elongate
member comprise, in one preferred embodiment of the invention, an
eye through which the graft may be threaded. The eye is preferably
formed by an annular extension of the elongate member. This annular
extension preferably has a cross-sectional dimension such that when
a graft is draped through the eye and the elongate member
positioned in the hole the graft will be firmly engaged on both
sides of the eye with the bone surrounding the hole. In this
embodiment of the invention the elongate member is preferably of
such a length that the eye will be only just completely inside the
hole at its condylar notch end. Such an arrangement ensures that
there is very little stretch of the graft within the hole. This
avoidance of relative motion between the graft and the surrounding
bone is believed to assist in the growth of bone into the graft and
thereby the establishment of an intimate bond between the bone and
the graft.
In the event that the graft comprises a number of graft strands
that are connected to the connection means by draping the graft
strands through an eye at the other end of the elongate member it
is advantageous if the shape of the eye is adapted to mimic the
natural connection of cruciate ligament to the femur. The femoral
attachment of cruciate ligaments, and particularly the posterior
cruciate ligament, to the femur is typically crescent shaped. As
the knee is flexed the various strands of the natural ligament will
be differentially tensioned. This situation may be imitated by
providing that the inside surface of the eye is arcuate with a
portion of that surface diametrically opposite the elongate member
closer to the elongate member than portions on either side of that
portion, i.e. the inside surface of the eye opposite the elongate
member bulges radially inwardly.
In a third aspect the present invention relates to connection means
for connecting a cruciate ligament graft to a patient's femur, the
connection means having a body that has at one end an eye or like
formation through which the graft may be threaded, the eye or like
formation having a bearing surface against which the graft will, in
use, bear, the bearing surface being arcuate along its length and
having a portion intermediate its ends that is closer to the body
of the connection means than portions on either side of that
portion.
In another embodiment of the invention the other end of the
elongate member is provided with a hook that can be positioned to
extend through a transverse hole through a bone block at an end of
the graft. There are circumstances in which the most suitable graft
will have a bone block at one. or both ends of the graft. The bone
block is preferably so sized that it is a tight fit in at least one
dimension in the hole as this will assist integration of the bone
block with the bone surrounding the hole.
In a preferred embodiment of the invention the tendon graft
comprises tendon or tendons derived from the hamstring tendons of
the patient or from the Achilles tendons of cadavers. Most
preferably, the tendons are the semitendonosus and gracilis tendons
of the patient harvested from the same leg as has the deficient
cruciate ligament. The invention could be practiced using
artificial tendon material or other bodily soft tissue such as
ligament. Suitable synthetic plastics materials have been proposed
for use in biological applications and could be used in place of
natural tendon.
The tendon or tendons forming the tendon graft are preferably
doubled over about their mid-point and trimmed to a desired length.
The free ends are preferably then bound together, over a length
approximately equal to the length of the tendons that will extend
through the hole in the tibia, after being threaded through the eye
in the connection device. Preferably, the ends of the tendon or
tendons will be bound together using a Krakow suture, a roman
sandal suture or a modified baseball stitch. A suture may also be
connected to the graft at the tibial end. This suture may be used
to draw the tendon graft through the tibial hole and to tension the
graft prior to insertion of the fixation device in the tibia. This
suture may also be used to connect the graft to fixation means on
the surface of the tibia.
The tibial hole is preferably formed by drilling a hole having a
cross-sectional area just sufficient to receive the other end
portion of the tendon graft. As the tendon graft may vary in
cross-sectional area along their length it is usual to position the
larger end of the tendon or tendons in the tibial hole. In the case
of an anterior cruciate ligament replacement a guide hole is
preferably drilled from the outside and is guided so that at its
exit from the tibia it will be at the coronal level of the median
tibial eminence 2/3 of the way across the notch, lateral to medial,
so as to remove the anterior cruciate ligament stump. The aim of
positioning is so that the final hole causes the graft to arise
from the centre of the notch coronally, sufficiently posterior to
avoid impingement with the roof of the notch at full extension of
the knee.
The graft may be secured in the tibia in any one of a number of
different ways. A screw could, for instance, be positioned between
the graft and the tibial bone surrounding the hole therein. In an
alternative, and more preferred, embodiment of the invention the
free end of the graft may be drawn right through the tibial hole
and secured, directly or by sutures, to the lateral surface of the
tibia by suitable fastening means such as staples, staple plates,
or screws. In the latter case both ends of the graft would be
anchored into cortical bone which has a number of obvious practical
advantages.
As it is preferred to connect the free end of the graft directly,
or through a suture, to the cortical bone on the surface of the
tibia it would be desirable to be able to bring the graft firmly
into contact with the tibial bone surrounding this hole in a manner
that substantially prevents movement of the graft within that hole.
In order to achieve this it is preferred that, when the graft is
made up of a number of strands, to position between the strands an
abutment means and to draw this abutment means tightly against the
graft strands and to urge them into contact with the tibial bone
around or within the hole.
In a fourth aspect the present invention relates to a method for
connecting a multi-strand graft to a bone comprising the steps of
causing the graft to extend through a hole in the bone, positioning
an abutment means between the strands of the graft and drawing the
abutment means against the strands of the graft to urge them into
contact with the bone surrounding the hole. The abutment means
preferably comprises a sphere or similarly shaped object, the
abutment means could, however be conical, frusto-conical, pyramidal
or any other suitable shape. The abutment means preferably has at
least one hole, more preferably at least two holes, extending
through it such that when the abutment means is in position in the
hole in the tibia the holes in the abutment means will extend
transversely to the axis of the hole in the tibia. Sutures are
preferably positioned to extend through the hole or holes in the
abutment means and through the hole in the bone, these sutures may
be used to pull the abutment means tightly into contact with the
bone surrounding the hole.
BRIEF DESCRIPTION OF DRAWINGS
The following description of a preferred embodiment of the present
invention is provided as an example of the invention and is
described with reference to the accompanying drawings, in
which:
FIG. 1 is a schematic perspective view of a patient's knee showing
the position of the semitendonosus and gracilis tendons and the
incision through which these tendons are harvested to form a
graft;
FIG. 2A is a perspective view of the component parts of a
connecting device according to the present invention;
FIG. 2B is a perspective view of the component parts of the
connecting device of FIG. 2A assembled together and connected to a
suture and to a graft;
FIG. 2C is a partially sectional view of a connecting device
according to a second embodiment of the present invention connected
to a graft having a terminal bone block;
FIG. 3 is schematic perspective view of the patient's knee showing
the positioning of an arthroscope and the drilling of a guide hole
for the formation of a femoral hole to receive one end of the
tendon graft;
FIG. 4 is a schematic perspective view showing a cannulated drill
on a beath pin being used to form the femoral hole;
FIG. 5 is a schematic perspective view showing the drilling of a
guide hole for a tibial hole to receive the other end of the tendon
graft;
FIG. 6 is schematic perspective view of drawing the tendon graft
through the tibial hole into the femoral hole;
FIG. 7 is a schematic perspective view showing the placement of a
connecting device to secure the one end of the tendon graft in the
femoral hole;
FIG. 8 is a detailed perspective view of a bead used to hold graft
strands in contact with the tibia;
FIG. 9 is a section along IX--IX of FIG. 8
FIG. 10 is a schematic perspective view showing the placement of a
screw to secure the other end of the tendon graft to the tibia;
FIG. 11 is a vertical sectional view of a connecting device
positioned in the femoral hole and securing the one end of the
tendon graft to the femur; and
FIG. 12 is a vertical sectional view of the other end of the graft
secured to the tibia.
BEST MODE FOR CARRYING OUT THE INVENTION
Operating Protocol
The following protocol assumes the operator will be securing a
graft 10 in replacement of an anterior cruciate ligament on the
femoral side 11 from within the joint and on the tibial side 12
externally. The graft 10 consisting of semitendonosus and gracilis
tendons 13 and 14 respectively is also assumed.
Preparation
Routine arthroscopy is performed prior to commencement of
reconstruction of the anterior cruciate ligament. Portal placement
is critical and can be described thus: the anterolateral portal
(not shown) is towards the top of the lateral triangle soft spot.
It is made with a transverse stab incision, aimed at the
intercondylar notch 15. The anteromedial portal 18 is lower than
usual, being 1 cm above the joint line and at the fat pad
reflection, with the blade aimed slightly up and towards the
intercondylar notch.
At this time, using the arthroscope in the anterolateral portal,
any meniscal repair or excision is carried out as well as any
debridement required for adequate visualisation of the joint in
general and the notch in particular. Often this requires partial
excision of the fat pad and particularly careful clearing of the
notch surface of the lateral condyle of the femur. The scar tissue
associated with the ruptured cruciate, the stump of the anterior
cruciate ligament and the plica interaricularis should also be
debrided. A curette is used to clear the lateral wall of the notch
and a suction shaver may be used to remove the resultant
debris.
The semitendonosus and gracilis tendons 13 and 14 are then
harvested as graft material. This should be done in whatever
fashion the operator is comfortable with, however, a single
incision 17 approximately 30 millimeters is all that is required.
The incision is medial to the tibial tubercle at the level of the
pes anserine insertion. The harvesting of the semitendonosus and
gracilis tendons 13 and 14 should result in at least 22 cm of the
tendons. Separation of the tendon should occur at the
musculo-tendinous junction. Care should be taken in harvesting the
tendons to ensure the accessory distal insertions of the
semitendonosus in particular are divided and do not divert the
harvesting tool into the body of the tendon.
After the tendons 13 and 14 are cleared of adherent muscle fibers
their length should be measured and the mid-point determined,
ideally this is 11 cm from the distal insertion of the tendons. The
broad surface of the semitendonosus 13 is wrapped around the tendon
mass using this tendon to give a smooth exterior surface to the
graft 10. The two tendons 13 and 14 are then doubled over an draped
through the eye 40 at one end of a connecting device 41 (see FIG.
2B). The connecting device 41 has at its other end a toggle 42
which has two holes 43 in it. A hook-like end 44 on the connecting
device 41 can extend through the holes 43 to pivotally connect the
toggle 42 to the connecting device 41. The four strand hamstring
tendon complex 10 may be sutured at its other end with a modified
roman sandal stitch 21 to hold the tendons 13 and 14 together.
The diameter of the tendon graft 10 is now measured at both the
proximal and distal ends, using a tube gauge. These diameters are
noted for appropriate drill sizing. Any free tissue in the graft 10
which may bunch up and obstruct the passing of the graft 10 through
the tibial and femoral drill holes should now be noted and
excised.
Having taken the graft, the arthroscope 24 is then inserted into a
central portal through a stab incision 25 over the patella tendon,
just below the inferior pole of the patella (not shown), thereby
allowing better visualisation of the back of the notch 15. Often it
is found that further clearing of the lateral wall of the notch 15
is required. This should be performed until the capsular attachment
is clearly visualised and palpated with a probe.
Femoral Drilling
A point 30.degree. from the top of the notch (11 o'clock in a right
knee; 1 o'clock in a left knee) and 5 mms from the back of the
notch 15 on the lateral wall is then identified and indented with a
burr. Care must be taken to avoid identifying the ridge of the
anterior edge of the original ACL attachment as the back of the
notch (resident's ridge). This error will lead to the femoral
tunnel being too anterior, compromising graft function. A 4.5 mm
drill 26 is then passed into the joint through the medial portal 16
and the tip placed in the burr hole while the knee is held at
90.degree. (the use of standard tissue protecting sleeves is
recommended). The drill is the spun a few turns to bed it into this
depression.
Holding the drill tip in the shallow hole thus created the knee is
pushed into as much flexion as it will achieve. Directing the drill
approximately 20.degree. anteriorly and 30.degree. laterally with
respect to the femur, a guide hole is then made, with drilling
ceasing as soon as the outer cortex is felt to have been pierced.
Withdraw the drill 26 and inspect the hole 29 to confirm position
by passing the arthroscope deep into the notch.
With the knee at 90.degree. flexion, a beath pin 27 is then passed
through the medial portal and up to the entrance of the guide drill
hole under direct vision. Care should be taken not to pass the pin
27 through the posterior cruciate ligament The knee is flexed
maximally and the pin 27 is passed up the guide hole and out
through the skin. This pin 27 serves as the guide for a cannulated
drill 28. With the knee held fully flexed a cannulated drill 28 of
a diameter matching the tendon graft, is then passed along the pin
27 and, under direct vision, the femoral hole 29 made.
The drill 28 is then removed and a nylon loop (not shown) threaded
into the eye 31 of the beath pin 27. With the loop end held, the
pin 27 is drawn out of the femur and the free ends of the nylon and
drawn through the femoral hole 29 and out of the thigh. Smoothing
of the edge of the femoral hole and debridement of any loose tissue
is now carried out.
The tibial hole is then made with the use of a guide 33. The tip 34
of the guide 33 is passed through the anteromedial portal 16 and
placed on a line from the anterior horn of the lateral meniscus to
the medial tibial spine and medially, one quarter of the way across
the intercondylar notch, that is just medial to the medial tibial
spine. The drill guide 33 then passes through the distal skin
incision 17 used for the harvesting of the hamstring tendon graft
10 and measures 40-45 mm distal from the cruciate ligament tibial
attachment. The 4.5 mm drill 35 is used to establish the line until
the cortex of the tibial plateau is reached, whereupon the guide is
removed and the drilling completed under direct vision. The final
position may be fine tuned by hand, so that the final drill
position will abut the medial eminence and remove the anterior
cruciate ligament stump. Having achieved satisfactory placement of
the 4.5 mm drill 35, a 2.0 mm guide wire (not shown) is passed into
the hole. The guide wire should intersect the PCL near its femoral
insertion to indicate correct drill hole placement and alignment. A
cannulated drill (not shown but similar to drill 28) of a diameter
equal to that of the tendon graft's distal end can now be
introduced over the guide wire. When tibial hole enlargement is
completed, the soft tissue at the entry to the joint can be cleared
with a shaver.
The suture 18 connected to one end of the toggle 42 is then used to
draw the connecting device 41 through the tibial hole 36 into the
femoral hole 29 until the toggle 42 is just drawn past the
posterior end of the hole 29. The suture 28 is connected to the
toggle 42 so that the toggle is caused to lie alongside the shaft
45 of the connecting device 41, which lies between the eye 40 and
the hook-like member 44. Once the toggle 42 is free of the hole 29
the tension in the suture 18 is released and suture 18a connected
to the other end of the toggle 42 is tensioned and the pull back in
order to pivot toggle 42 into a position in which it lies against
the outside face of the femur adjacent the femoral hole 29. The
tendon complex 10 is thus connected to the femur.
A bead 46, having orthogonally arranged holes 47 formed through it,
is previously positioned between the four strands of tendon 13 and
14. Sutures 48 extend through the holes 47 in the bead and one end
of one suture is positioned to extend between each of the tendon
strands 13 and 14.
The end of the suture 21 and the ends of the sutures 48 are then
pulled into tension in the tibial thereby drawing the tendon
complex 10 hole 36 and drawing the bead 46 firmly into contact with
the tendon strands 13 and 14. The tension transferred by the
sutures 48 to the bead 46 forces the tendon strands which typically
are thicker at the tibial end into contact with the tibial bone
surrounding the tibial hole 36. The contact between the tendon
strands 13 and 14 and the tibial bone helps integration of bone
growth into the tendon in two ways. Firstly it prevents
longitudinal movement of the tail of the tendon complex 10 within
the tibial hole 36 (called `pistoning`) which prevents the growth
of solid bone and secondly the pressure of the tendon on the bone
itself promotes bone growth.
Having fixed the femoral end of the tendon graft 10, the knee is
placed at 90.degree. flexion and the tibial end 23 drawn down
firmly, thereby applying tension to the graft 10. Isometricity may
be tested at this time as the knee is extended and flexed. Having
achieved the desired tension and positioning of the graft 10. While
maintaining distal tension on the graft 10, and holding the knee at
30-45.degree. of flexion, a screw 41 is inserted into the tibia
outside the tibial hole 36 and the suture 21 connected to it in a
known manner.
The motion of the knee, Lachman test, anterior draw and pivot shift
test are finally checked. The knee is copiously irrigated to remove
debris. A drain is passed into the joint using the arthroscopic
procedure and directly laterally. Routine closure and
post-operative care is followed.
It will be appreciated by persons skilled in the art that numerous
variations and/or modifications may be made to the invention as
shown in the specific embodiments without departing from the spirit
or scope of the invention as broadly described. The present
embodiments are, therefore, to be considered in all respects as
illustrative and not restrictive.
* * * * *